WO2002057501A1

WO2002057501A1 - Heating furnace with regenerative burners and method of operating the heating furnace

Info

Publication number: WO2002057501A1
Application number: PCT/JP2001/011508
Authority: WO
Inventors: Ichiro Sugimoto; Kenta Karube; Masahiro Furukawa; Kazunari Andachi
Original assignee: Kawasaki Steel Corporation
Priority date: 2001-01-17
Filing date: 2001-12-27
Publication date: 2002-07-25
Also published as: DE60124691T2; CA2639404A1; CA2403221A1; EP1275740A4; CN1427897A; EP1275740B1; EP1757707A2; CA2403221C; DE60124691D1; KR100634776B1; KR20020083180A; TW524956B; CN100338236C; EP1275740A1; US6644962B2; US20030027095A1; ATE346172T1; EP1757707A3; BR0109303A

Abstract

A heating furnace with regenerative burners and a method of controlling a furnace pressure; the heating furnace, comprising a plurality sets of regenerative burners having preheat zones, heating zones, uniform zones, and, as heat sources of the uniform heating zones, pairs of burners with heat reservoirs disposed opposedly to each other; a method of controlling the furnace pressure in the uniform heating zones, comprising the step of controlling the sucking rate of exhaust gas from the burners to the heat reservoirs according to the combustion load of the entire heating furnace, whereby the furnace pressure can be strictly controlled by utilizing regenerative burner-specific mechanisms when operating the heating furnaces with less heat loss re-utilizing the heat of the exhaust gas for the pre-heat of combustion air for the burners by using the regenerative burners as the heating sources of the continuous heating furnace.

Description

Specification

TECHNICAL FIELD The present invention relates to a heating furnace having a regenerative parner and its operating method.

The present invention relates to a method for optimally controlling a furnace pressure of a heating furnace. The present invention relates to a method for controlling the atmosphere in a heating furnace, and particularly to a method for suppressing an increase in oxygen concentration in the atmosphere. TECHNICAL FIELD The present invention relates to a method for operating a heating furnace having a regenerative parner, and more particularly to an operating method for advantageously performing alternating combustion of a pair of parners in a regenerative parner and a heating furnace used directly in this operation. It is. The present invention relates to a method for measuring the concentration of atmospheric gas in a heating furnace and a heating furnace. Background art

Steel heating furnaces are used for the purpose of reheating steel slabs rough-rolled in a lump mill or continuously manufactured slabs to final products at a predetermined temperature suitable for the rolling. I have. This heating furnace is roughly classified into a patch type and a continuous type. Each has its strengths and weaknesses, so they are selectively used according to their purpose. Continuous heating furnaces are widely used in steelworks because they are suitable for mass production in recent years.

Figure 1 shows a typical example of a sectional view of a continuous heating furnace. Generally, it consists of the pre-tropical zone 1, the heating zone 2 and the average tropical zone 3 in order from the loading side of the steel material. At least the heating zone 2 and the average tropical zone 3 are heated and maintained at a predetermined temperature by the pana 4. The steel material 5 introduced into the pre-tropical zone 1 from the charging door 1 a moves on the transport path 6, is heated to a predetermined temperature through the heating zone 2 and the soaking zone 3, and is extracted to the predetermined temperature in the soaking zone 3 a From the furnace. Exhaust gas generated by the combustion of the parna 4 is discharged out of the furnace through a flue 7 provided at the entrance of the pre-tropical zone 1. 7a is a recuperator for exchanging the sensible heat of the flue gas in the flue gas with the sensible heat of the air for burner combustion, and 7b is a damper for furnace pressure control. Here, in the continuous heating furnace, it is necessary to heat the steel material to a temperature suitable for the subsequent rolling process. If the temperature of the steel material heated in the continuous heating furnace falls below the predetermined lower limit of the rolling temperature, the rolling operation and product quality will be adversely affected. On the other hand, if the temperature of the steel material extracted from the heating furnace rises more than necessary, the heat loss in the continuous steel heating furnace will increase. It becomes important to heat with fuel. Further, in the heating furnace, it is also required to adjust the heating time so that the heated steel material is sequentially supplied from the heating furnace in accordance with the rolling pitch in the rolling process.

In a continuous heating furnace, heat loss, especially radiant energy loss from the heating zone, is large. Pre-tropical and solitary zones are placed on the entrance and exit sides of the heating zone, and the furnace is partitioned into three sections to reduce heat loss.

The steel material to be charged into the continuous heating furnace includes a piece cooled to room temperature, and a hot charge material immediately sent to the rolling process immediately after continuous production, and the temperature at the heating furnace entrance side varies. The heating temperature varies widely, and the throughput of the steel material to be heated in the heating furnace also varies. It is necessary to control the temperature inside the furnace according to these various conditions. The heating temperature is adjusted by increasing or decreasing the burner amount of the parner. At this time, the furnace pressure fluctuates due to the change in the burner amount of the wrench.

When the pressure inside the furnace becomes lower than the pressure outside the furnace, external air enters the furnace from the charging door and the extraction door, which are the openings of the heating furnace. When air enters the furnace, the temperature inside the furnace decreases and the burner burns more. Fuel consumption increases and costs rise. When air enters the furnace, the oxygen concentration in the furnace atmosphere increases, which promotes oxidation, nitridation, or decarburization of the surface of steel and the like charged in the furnace. As a result, the surface quality of the steel material will be degraded.

Therefore, it is necessary to control the pressure inside the heating furnace appropriately. Various proposals have been made for furnace pressure control. For example, JP-A-61-119 According to No. 987, according to the amount of exhaust gas generated in the furnace, the setting of the soaking zone in the heating furnace is controlled to a positive pressure (hereinafter simply referred to as positive pressure) with respect to the pressure outside the furnace, It also discloses that air can be prevented from entering through the extraction door. According to this method, it is possible to control the furnace pressure in the upper region (hereinafter referred to as the upper zone) bordering on the transfer path in the area to a positive pressure. However, when the combustion load of the entire heating furnace is small, the furnace pressure in the lower region (hereinafter referred to as the lower zone) bounded by the transfer path in the furnace is a negative pressure (hereinafter simply referred to as negative pressure) with respect to the pressure outside the furnace. Pressure). It was difficult to reliably prevent air from entering through the gap below the loading and extraction doors. It has been difficult to reliably prevent air from entering through the so-called extra oak opening, in which these doors mesh and close together. The comb-shaped opening of the extract rough oak is 3c shown in Fig.14.

Further, Japanese Patent Application Laid-Open No. 9-209032 discloses that a furnace pressure damper provided in a flue through which exhaust gas from a heating furnace passes above a solitary tropic zone, and the furnace pressure is adjusted according to the fuel load of the heating furnace. Optimum control is disclosed. However, when the combustion load is small, the draft of the flue is larger than the pressure loss due to the flow of exhaust gas from the furnace to the flue. Draft is a phenomenon in which buoyancy is generated in the gas heated in the flue / furnace, resulting in negative pressure. In this case, it is difficult to make the lower zone positive by the furnace pressure damper. It was difficult to reliably prevent air from entering through the charging and extraction doors.

Japanese Patent Application Laid-Open No. 7-316645 discloses a method in which a gas supply piping system is connected to the outlet of a recuperator of a stack to blow gas such as air into the stack to control furnace pressure. In this method, it is necessary to provide a new blower, various pipes, and a control system to control the furnace pressure. There is a problem in that the equipment costs are high and the maintenance is complicated. In addition, since the equipment around the heating furnace is complicated and complicated, it is difficult to install a new control system because there is no space to install it.

Preventing air from entering the furnace is a matter of product quality and processing. This is extremely important for the operation of the furnace. Various techniques have been proposed for that purpose. For example, in Japanese Patent Application Laid-Open No. 11-172326, flammable gas is ejected from a nozzle provided near the extraction port separately from the heating parner inside the furnace in order to prevent air from entering from the extraction port of the heating furnace. Then, it has been proposed to consume the oxygen in the invading air by the combustion at that time.

However, it is necessary to provide a dedicated flammable gas ejection nozzle near the extraction port, which increases equipment costs. In addition, it is effective for air entering from above the location of the jet nozzle, but less effective for air entering from below the location of the jet nozzle. Since the furnace pressure is negative below, it is inevitable that air will enter this area. In particular, it was difficult to reliably prevent air from entering through the opening of the extra oak.

In recent years, in continuous heating furnaces, heat storage furnaces have been used as heat sources, and the heat in exhaust gas has been reused for preheating combustion air for the burners, and operation of the heating furnaces with low heat loss has been performed. . Figures 2A and 2B show examples of the structure of a regenerative burner. As shown in the examples of FIGS. 2A and 2B, the regenerative pan is composed of a pair of pans 40a and 40b, which are placed facing each other between both side walls of the heating furnace soaking body 3. In addition, dual passages 41a and 41b for guiding combustion air from outside the furnace to each parner and for guiding exhaust gas inside the furnace to the outside of the furnace through each parner, and in the example shown, the opening on the parner side of each passage. And heat storage elements 42a and 42b. This regenerative type burner alternately burns the pair of burners. For example, as shown in FIG. 2A, when the combustion air is supplied to the parner 40a from the shared passage 41a, the fuel 43a is supplied, and when the parner 40a is burned, Exhaust gas in the furnace is sucked from a parner 40b facing the furnace, the exhaust gas is passed through a heat storage body 42b to recover heat, and then guided to a combined passage 41b to be discharged out of the furnace.

Next, after switching the combustion operation of the wrench and switching the switching valve 44 of the shared passage 41a and 41b to change the connection with the air and exhaust gas conduits described above, as shown in FIG. Got it, PANA 40B double-purpose When supplying combustion air from the passage 41b via the heat storage body 42b, preheating of the combustion air is performed using the heat recovered in the heat storage body 42b in the process shown in Fig. 2A. While supplying fuel 43b to burn the burner 40b. At the same time, the exhaust gas in the furnace is sucked from the opposing parner 40a, the exhaust gas is passed through the heat storage body 42a to recover heat, and then guided to the shared passage 41a to be discharged out of the furnace.

By repeating the above-mentioned alternating combustion of the wrench shown in FIGS. 2A and 2B, for example, every several tens of seconds, it is possible to operate the heating furnace with little heat loss.

Here, the exhaust gas is sucked from the wrench during non-combustion, for example, from the wrench 40a or 40b via the regenerator 42a or 42b as shown in FIGS. 2A and 2B. At the end of the path 45, for example, a suction device 8 using a suction fan is arranged, and the suction device 8 is driven to suck exhaust gas from the wrench.

However, in the operation of the heating furnace using the regenerative parner described above, the period from the start of combustion of the panner to the set temperature or the furnace atmosphere is reduced to a low temperature range of about 800 ° C. When controlled, the temperature of the exhaust gas sucked from the wrench and passing through the regenerator also decreases. As a result, moisture and sulfur contained in the exhaust gas will condense on the exhaust gas outlet side of the heat storage body and on the subsequent route 45 described above. The liquid, so-called drain, generated by this condensation may stay on the exhaust gas discharge side of the heat storage body. If the combustion operation of the burner is switched to the combustion state as it is, the mixture of drain into the combustion air will cause a problem that the combustion flame temperature will drop. The reduction in combustion flame temperature due to this drain not only reduced the thermal efficiency of the heating furnace, but also hindered low-temperature operation.

In addition, in a heating furnace equipped with a number of regenerative parners, there is a long path for introducing low-temperature exhaust gas from the parner through the regenerator to the suction device. Drainage may occur not only on the outlet side of the heat storage unit, but also on the above route. Drain generated on this path corrodes the impeller of the suction device. If the solid content in the drain wears and damages the impeller, it could lead to a serious accident. For this reason, in the past, heating furnaces with regenerative burners had been frequently inspected for exhaust gas suction devices. In addition, the increase in the cost required for frequent repairs such as replacement of the impeller of the suction device was also a problem.

To cope with the above-mentioned problems relating to drainage, Japanese Patent Application Laid-Open No. 10-30812 discloses an apparatus shown in FIG. Exhaust gas in the heating furnace (for example, in the solitary zone 3) is flown into the exhaust gas pipe line 50 through the bypass pipe 51 separately from the path to be discharged outside the furnace through the parner 40a and the exhaust gas pipe line 50. It is disclosed that by doing so, the temperature in the exhaust gas piping 50 is maintained at or above the dew point of the exhaust gas.

However, if the steel is heated at a relatively low temperature for a long time to make the temperature uniform in the thickness direction of the steel material, or if high load combustion is not possible due to equipment traps, burn the burner with an extremely low load. Need to be done. In this case, the operation of the suction device (fan) is reduced to, for example, less than 10% of its suction capacity, and as a result, the operation of the suction device may become unstable. A swirl flow cannot be obtained stably over the entire surface of the fan blades, and a stall may occur where swirl flow cannot be obtained. Then, it becomes difficult to keep the exhaust gas suction amount from the wrench constant, and abnormal vibration occurs in the power blade, and in some cases, the fan may be damaged.

As described above, the technology described in Japanese Patent Application Laid-Open No. Hei 10-30812 solves the problems related to drainage when burning at low load, but solves the problem that the operation of the suction device becomes unstable. Not done. In addition, since there are control valves in each of the exhaust gas pipe line 50 and the bypass pipe 51 described in the publication, there is also a problem that the control is complicated.

In a continuous heating furnace, it is important to strictly control the atmosphere in the furnace in order to maintain the surface of the steel material being heated in good condition. For example, when the oxygen concentration in the furnace atmosphere increases, the surface oxidation, nitriding, or decarburization of the material to be heated, such as steel, charged in the furnace is promoted, and the rolling is performed as it is. The surface quality of the product is reduced. To improve or maintain product quality, it is necessary to suppress the increase in oxygen concentration in the furnace atmosphere. For that purpose, it is important to accurately measure the oxygen concentration in the furnace atmosphere. In addition to the oxygen concentration, it is also important to accurately measure the concentration of nitrogen, carbon monoxide, nitrogen oxides, etc. in the furnace atmosphere. Nitrogen affects the nitridation of steel surfaces, carbon monoxide can be used to detect incomplete combustion of the wrench, and nitrogen oxides are needed to control environmental emission standards.

Here, Japanese Patent Application Laid-Open No. 62-40312 discloses that each probe for measuring the oxygen concentration and the CO concentration in a heating furnace is movable, and the concentration is measured at a plurality of measurement positions. It discloses that the air ratio of the wrench is corrected and controlled by calculating the average concentration value.

However, equipment costs are high because it is necessary to newly install a drive system and a control system to measure the concentration. If the maintenance is complicated, and the heating furnace is complicated with ducts and other equipment, there is no space for installation and it is difficult to provide a new drive system or control system. There were many.

Also, in Japanese Patent Application Laid-Open No. Hei 9-53120, a partition wall is installed in the furnace width direction inside the furnace wall on the extraction side of the heating furnace and below the skid, and a partition wall between the partition wall and the extraction side furnace wall is provided. Discloses a heating furnace having an exhaust pipe for discharging an oxygen concentration meter atmosphere gas outside the furnace. It is disclosed that in this heating furnace, the flow rate in the exhaust pipe is controlled while measuring the oxygen concentration using the oxygen concentration meter.

However, in order to perform measurement with an oximeter between the partition wall and the extraction furnace wall, it is necessary to insert a probe from the hearth or the furnace wall. When a probe is inserted from the hearth, the probe may be damaged or clogged due to the dropping and accumulation of scale, etc., making it difficult to perform reliable concentration measurement over a long period of time. In addition, when the probe is inserted from the furnace wall, the probe is exposed to the high temperature area in the furnace and bends, causing the measurement points to shift or be damaged. May occur. Disclosure of the invention

An object of the present invention is to propose a furnace pressure control method that can reliably prevent air from entering a heating furnace.

The inventors have eagerly studied the intrusion of air when the pressure in the furnace becomes negative. Air enters the furnace from both the loading door and the extraction door. As shown in Fig. 1, a flue 7 is provided immediately after the charging door 1a. The air that has entered through the charging door la immediately passes through the flue 7 and is discharged outside the furnace. It was found that air entering through the charging door 1a was unlikely to cause a rise in the oxygen concentration in the furnace and a decrease in the furnace temperature. Increasing the oxygen concentration in the furnace ゃ To avoid a decrease in the furnace temperature, it is important to avoid the intrusion of air from the extraction door. To this end, we found that it was important to control the furnace pressure in the solitary tropics where the extraction door was installed. As described above, the furnace pressure is controlled by opening and closing the damper provided in the flue, especially when the combustion load is small, by setting the furnace pressure in the lower part of the transport path in the solitary zone to a positive pressure. It is difficult. This is because the amount of exhaust gas generated decreases, and the pressure loss of the exhaust gas from the inside of the furnace to the flue decreases, while the draft increases in the furnace downward. Furnace pressure distribution gradually decreases relatively below the heating furnace. In the lower zone, the draft is larger than the pressure loss of the exhaust gas and negative pressure is likely to occur.

At this time, a regenerative furnace has been used as a heating source for the continuous furnace, and the heat in the exhaust gas is reused for preheating the combustion air of the parner. . We examined furnace pressure control of a heating furnace using a regenerative parner. In particular, when a regenerative panner is used as a heating source in the lower part of the solitary tropics, strict furnace pressure control is possible by using a mechanism unique to the regenerative panner. Heading, and completed this invention.

That is, the present invention relates to a heating furnace using a regenerative A furnace pressure control method using a regenerative burner, characterized by controlling the furnace pressure in the solitary zone by adjusting the exhaust gas suction rate from the above-mentioned burner to the regenerator according to the combustion load of the entire furnace. It is.

Furthermore, the present inventors have eagerly studied a method capable of keeping the furnace pressure in the region below the transport path in the solitary zone positive even when the combustion load is small. It was found that diversion air supplied to the regulator inlet side of the flue could be used for furnace pressure control for the purpose of protecting the furnace.

That is, according to the present invention, when a recuperator is arranged in the middle of a flue that guides exhaust gas in a heating furnace to the outside of the furnace, and when the recuperator preheats combustion air supplied to a burner that is a heating source of the heating furnace, In order to protect the recuperator from high-temperature atmosphere, when supplying diluent air to the recuperator inlet side of the flue, the flow rate of the diversion air depends on the exhaust gas temperature on the recuperator inlet side and the combustion load of the heating furnace. This is a furnace pressure control method for a heating furnace, characterized in that the furnace pressure is adjusted by controlling the furnace pressure. One of the objects of the present invention is to propose a method capable of reliably preventing air from entering the heating furnace from the extraction door. One of the objects of the present invention is to provide a heating furnace used in this method.

The inventors have elaborated on the intrusion of air when the pressure in the furnace becomes negative.In this case, air enters the furnace from both the charging door and the extraction door. As shown in Fig. 1, the flue 7 is provided immediately after the charging door 1a, so the air that has entered through the charging door 1a immediately passes through the flue 7 and is discharged outside the furnace. As a result, it was found that it was difficult to cause an increase in the furnace oxygen concentration and a decrease in the furnace temperature. Therefore, in order to avoid an increase in the oxygen concentration in the furnace and a decrease in the temperature in the furnace, it is important to avoid the intrusion of air from the extraction port. For that purpose, it is necessary to surely shut off the intruding air at the extraction end. Has come to realize that it becomes important.

One of the objects of the present invention is when the combustion load of the regenerative It is an object of the present invention to propose a method of operating a heating furnace in which the operation of the exhaust gas suction device does not become unstable. Another object of the present invention is to provide a heating furnace used in the method for operating the heating furnace.

The present inventors have proposed a method of increasing the operating load of a regenerative burner when the combustion load of the regenerative burner is reduced and the exhaust gas suction device must be operated at a load of, for example, less than 10%. The present inventors have found that it is extremely advantageous to guide the exhaust gas from a flue that guides the exhaust gas of the heating furnace to the outside of the furnace to the suction device, and have completed the present invention.

One of the objects of the present invention is to propose a method capable of accurately measuring the concentration of a component gas in a furnace atmosphere using existing equipment. Another object of the present invention is to provide a heating furnace capable of measuring the concentration of a component gas in the atmosphere inside the heating furnace.

In the operation of a heating furnace using a regenerative parner, the steps shown in Figs. 2A and 2B are repeated, for example, every several tens of seconds, and heating is performed, so that heating furnace operation with little heat loss is performed. Is realized.

In the operation of a heating furnace using such a regenerative burner, the exhaust gas from the regenerative burner is sucked at high speed, so exhaust gas distributed in the furnace width direction is sucked over a wide range. The inventors focused on this phenomenon, and measured the component concentration of the exhaust gas sucked from the regenerative parner, because the exhaust gas in the furnace sucked from the regenerative parner reproduced the atmosphere inside the furnace well. The inventors have found that the concentration of components in the furnace atmosphere can be accurately measured by performing the method described above, and have completed the present invention.

The gist of the present invention is as follows.

1. A heat storage type pan having a pre-tropical zone, a heating zone and a soaking zone, and a plurality of regenerative pans arranged with a pair of panners with heat storage bodies facing each other as a heat source of the solitary zone. In the furnace, each pair of regenerative burners is burned alternately, and when not burning, the exhaust gas in the furnace is sucked from the furnace and the exhaust gas is introduced into the regenerator to recover the heat in the exhaust gas into the regenerator. And This recovered heat is used to heat the combustion air of the burner during combustion, and the operation of the heating furnace is carried out. In accordance with the combustion load of the entire heating furnace, the exhaust gas from the above-mentioned burner to the heat storage unit is used. A furnace pressure control method using a regenerative parner, characterized in that the suction pressure is adjusted to control the furnace pressure in the solitary zone.

2. A recuperator is placed in the flue that guides the exhaust gas from the heating furnace to the outside of the furnace. When the recuperator preheats the combustion air supplied to the burner heating source, the recuperator is heated to a high temperature. In order to protect from the atmosphere, when supplying diluent air to the recuperator inlet side of the stack, the diluent air flow rate is adjusted according to the exhaust gas temperature at the recuperator inlet side and the combustion load of the heating furnace. A furnace pressure control method for a heating furnace, characterized by adjusting and controlling the furnace pressure.

3. When the extraction door of the heating furnace is opened, the combustion of the heating parner, which is located in the lower area of the furnace extraction end, is controlled independently of the heating parners arranged in the heating furnace. The frame of the parner is extended in the width direction of the extraction port across the width of the opening, and the entrance path of air from the extraction port is blocked by the panner frame to suppress an increase in the oxygen concentration in the furnace. An atmosphere control method for a heating furnace, characterized in that:

4. In 3., a partition wall rising from the hearth was provided inside the heating parner at the furnace extraction end to form a rising flow along the partition wall, and the air entering from the extraction port was raised A method for controlling the atmosphere of a heating furnace, characterized by being placed in a flow.

5.3 The atmosphere control method for a heating furnace according to 3 or 4, characterized in that the heating parner arranged at the furnace extraction end is operated at a low air ratio under combustion. 6. In a heating furnace, which has a regenerative parner with a pair of parners provided with a heat accumulator facing each other as a heating source, the parners of each pair of the regenerative parners are alternately burned in a heating furnace. Exhaust gas in the furnace is sucked from the furnace during combustion, the exhaust gas is introduced into the regenerator, heat in the exhaust gas is collected in the regenerator, and the recovered heat is used to heat the combustion air of the parner during combustion. When operating the heating furnace, the combustion load of the regenerative A method for operating a heating furnace having a regenerative burner, wherein hot air is supplied to a suction device for sucking exhaust gas in the furnace from the non-burning panner through a regenerator when the size is small. .

7. The operating method of the heating furnace according to 6, wherein the hot air is an exhaust gas in a flue that guides the exhaust gas in the heating furnace out of the furnace.

8. In a heating furnace, which has a regenerative parner with a pair of parners provided with a heat accumulator facing each other as a heating source, the parners of each pair of the regenerative parners are alternately burned in a heating furnace. Exhaust gas in the furnace is sucked from the furnace during combustion, the exhaust gas is introduced into the regenerator, heat in the exhaust gas is collected in the regenerator, and the recovered heat is used to heat the combustion air of the parner during combustion. At the time of operating the heating furnace using the heating furnace, a part of the exhaust gas sucked from the above-mentioned wrench is guided to an analyzer to measure the concentration of components in the exhaust gas. How to measure gas concentration.

9. The heating furnace according to 9.8, wherein the measured value of the component concentration of the exhaust gas sucked from the regenerative parner is used as a representative value of the component concentration in a zone in the reheating furnace provided with the regenerative parner. Method for measuring the concentration of atmospheric gas in a room.

10. As a heat source, a plurality of regenerative parners arranged opposite to each other with a pair of panners provided with a heat accumulator are provided, and the pairs of the regenerative parners are alternately burned. In addition, the exhaust gas in the furnace is sucked from the burner during non-combustion, the exhaust gas is introduced into the heat accumulator, heat in the exhaust gas is collected in the heat accumulator, and the recovered heat is used for the combustion air of the burner during combustion. In reheating furnaces that operate for heating, at least the regenerative burner located in the lower region of the extraction end of the reheating furnace has a combustion control system that is independent of other regenerative burners. And heating furnace.

11. The heating furnace according to 11.10, wherein a partition wall rising from the hearth is provided at a position sandwiching a regenerative parner having an independent combustion control system with an extraction door of the heating furnace.

1 2. As a heat source, face to face a pair of wrench with heat storage And a pair of the regenerative burners is burned alternately, and the exhaust gas in the furnace is sucked from the non-burning burner to discharge the exhaust gas into the regenerator. Introduces the heat in the exhaust gas into the heat storage unit and uses the recovered heat to heat the combustion air of the burner during combustion, and operates the furnace. In the heating furnace, the exhaust gas in the heating furnace is not burned A suction device is provided at the end of a path for suctioning the heat from a wrench through a heat storage element, and a piping path for guiding hot air to the suction device via an on-off valve is provided on the suction device inlet side of the path. Characterized heating furnace.

13. The pipe line according to item 12, wherein the piping is connected to a flue that guides exhaust gas in the heating furnace to the outside of the furnace, and guides the exhaust gas in the heating furnace as hot air. heating furnace.

14. A heating furnace according to item 14 or 13, wherein a recuperator is provided on an upstream side of a pipe line of the stack.

15 5. As a heating source, a regenerative parner is provided with a pair of parners with a heat storage body attached to each other, and the parners of each pair of the regenerative parners are alternately burned and not burned. The exhaust gas in the furnace is sucked from the furnace, the exhaust gas is introduced into the heat storage body, the heat in the exhaust gas is recovered by the heat storage body, and the recovered heat is used for heating the combustion air of the parner during combustion. In a heating furnace where operation is performed, a probe for sampling a part of the exhaust gas and a component concentration of the collected exhaust gas in the course of discharging the exhaust gas in the heating furnace from a non-burning burner through a heat storage unit. A heating furnace provided with an analyzer for measuring the temperature. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the structure of a continuous heating furnace.

FIG. 2A is a diagram showing the structure of a regenerative parner.

FIG. 2B is a diagram showing the structure of a regenerative parner.

FIG. 3 is a diagram showing an exhaust gas discharge path in a conventional heating furnace.

FIG. 4 is a diagram showing an exhaust gas discharge path in the heating furnace according to the present invention. FIG. 5 is a diagram showing the structure of the continuous heating furnace used in the present invention.

FIG. 6 is a diagram showing the relationship between the exhaust gas suction rate and the furnace pressure.

FIG. 7 is a diagram showing the relationship between the furnace pressure and the amount of air entering.

FIG. 8 is a view showing the structure of a continuous heating furnace used in the present invention.

Figure 9 is a diagram showing the relationship between the opening degree of the dilution air flow control valve and the furnace pressure.

FIG. 10 is a diagram showing the relationship between the furnace pressure control method and the furnace pressure and the oxygen concentration in the furnace.

FIG. 11 is a diagram showing the relationship between the furnace pressure control method and the furnace pressure.

FIG. 12 is a diagram showing the relationship between the furnace pressure control method and the oxygen concentration in the furnace.

FIG. 13 is a diagram showing the arrangement of the heating parner in the furnace.

FIG. 14 is a diagram showing the extraction port of the heating furnace.

Figure 15 is a diagram showing the air flow near the heating furnace extraction end.

Fig. 16 is a diagram showing the relationship between the air ratio of the heating parner and the combustion amount of intruding air.

FIG. 17 is a diagram showing a discharge path of the exhaust gas from the regenerative parner.

Figure 18 compares the measured oxygen concentration in the furnace and the average oxygen concentration in the furnace by various methods. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the method of the present invention will be described in detail with reference to the drawings. FIG. 5 shows a continuous heating furnace used directly in the method of the present invention. This heating furnace is basically the same as that shown in FIG. 1, except that the regenerative parners 40a and 40b shown in FIG. 2A and FIG. This is an example in which a plurality of sets are arranged below the transport path 5. In FIG. 5, reference numerals 40a and 40b are included, including the shared passage and the heat storage element. In the operation of the heating furnace, the furnace pressure is controlled by adjusting the rate of exhaust gas suction from the above-mentioned burners 40a and 40b to the regenerators 42a and 42b according to the combustion load of the entire heating furnace. Specifically, the furnace pressure in the lower zone is controlled to be positive. There is a characteristic in the place.

In other words, in the operation of the heating furnace, the furnace pressure was measured with a furnace pressure gauge installed in the lower part of the soaking zone, and the flow rate of exhaust gas passing through the heat storage body of the regenerative parner was adjusted by a flow control valve in accordance with the target furnace pressure. By controlling the furnace pressure, the furnace pressure in the lower zone, especially in the lower part of the solitary zone, is controlled to the target furnace pressure by controlling the exhaust gas suction rate.

Figure 6 shows the relationship between the exhaust gas suction rate and the furnace pressure. The graph shows the relationship between the furnace pressure in the lower subtropical zone and the exhaust gas suction rate when the exhaust gas suction rate is adjusted according to the combustion load by the above method. Exhaust gas suction rate and furnace pressure are almost inversely proportional. The furnace pressure can be strictly controlled by adjusting the exhaust gas suction rate. Note that the exhaust gas suction rate is a ratio of the amount of exhaust gas sucked into the regenerative burner to the amount of exhaust gas generated by combustion of the regenerative burner. It is determined by actually measuring the exhaust gas flow rate using an exhaust gas flow meter installed in the exhaust gas duct of a regenerative parner.

Further, it is preferable that the furnace pressure be controlled in the range of 0 to 0.5 ram Aq by controlling the exhaust gas suction rate as described above. If the furnace pressure in the lower part of the soaking zone is set to 0.5 mmAq or more, the furnace pressure in the upper part of the soaking zone becomes too high, and the gas in the furnace blows out of the furnace, which may damage the extraction door. Fuel intensity also deteriorates.

FIG. 8 shows a continuous heating furnace used directly in the method of the present invention. This heating furnace has basically the same configuration as shown in Fig. 1. If the furnace exhaust gas introduced into the recuperator 7a exceeds the upper limit of the heat-resistant temperature of the recuperator 7a, the dilution air 8 is supplied to the inlet of the recuperator 7a of the flue 7 It has a structure that protects the recuperator 7a.

In the operation of a heating furnace with such a structure, in addition to the case where the exhaust gas temperature exceeds the heat-resistant temperature of the recuperator 7a and the case where the furnace pressure in the lower part of the tropical zone 3, especially the lower part, falls below the target value, Supply lysis air 8. By supplying a predetermined flow rate of the diffusion air 8, a uniform The feature is that the furnace pressure in the lower part of 3 is controlled to be positive. That is, as shown in Fig. 8, the furnace pressure measured value P.1 by the furnace pressure gauge 3b installed in the lower part of the isotropical zone 3 is compared with the target furnace pressure (positive pressure) by the computing unit 9a. Based on the result, the arithmetic unit 9a first sets the opening of the damper 7b for furnace pressure control, and performs furnace pressure control.

In this normal operation, the temperature measurement value T.1 at the thermometer 7c provided on the inlet side of the recuperator 7a of the stack 7 and the target temperature of the exhaust gas at that position, that is, the upper temperature limit of the recuperator 7a Are compared by the computing unit 9b. When the measured temperature value T.1 approaches the upper limit of the heat-resistant temperature of the recuperator 7a, it is supplied to the ventilation fan 8a for supplying the direction air 8 and the flow control valve 8b according to a command from the calculator 9b. Provide an appropriate fan speed and flow control valve opening. By supplying the dilution air 8 having a predetermined flow rate to the flue 7 and mixing the dilution air 8 with the exhaust gas, the temperature of the exhaust gas introduced into the recuperator 7a is reduced to an allowable range. When the measured temperature T.1 becomes equal to the above target temperature, fix the fan speed and the flow control valve opening.

On the other hand, in the above-mentioned normal operation, for example, when the combustion load of the furnace becomes small and the furnace pressure measurement value P. 8a and the flow control valve 8b are given an appropriate fan rotation speed and flow control valve opening, respectively, to supply the dilution air 8 of a predetermined flow rate to the flue 7 and to increase the furnace pressure. Measure. That is, when the dilution air 8 is supplied to the flue 7, the gas flow rate passing through the flue 7 increases, so that the pressure loss in the flue 7 rises and the furnace pressure rises. As a result, the furnace pressure in the lower part of the tropical zone 3 is prevented from becoming negative. When the measured furnace pressure P.1 becomes equal to the target furnace pressure, the fan speed and the flow control valve opening are fixed.

Figure 9 shows the relationship between the opening of the flow control valve of the diffusion air 8 and the furnace pressure in the lower part of the soaking zone 3. By controlling the flow rate of the dilution air 8, the control range of the furnace pressure becomes extremely large. The burn load of PANA is small Even in this case, it is possible to easily make the furnace pressure in the lower region of the isotropical zone 3 positive by supplying the diurision air 8. Moreover, there is no need to make new capital investments because existing facilities are used.

In the continuous heating furnace shown in Fig. 1, of the plurality of heating parners 4 arranged in the furnace, the heating parner 40 arranged in the lower region of the furnace extraction end is used for other heating parners 40. An independent control system different from the parner 4 is introduced to control the combustion of the heating parner 40 independently.

Here, as shown in Fig. 13, the burner 4 in the heating furnace is generally provided with its pair 4a and 4b facing each other between the side walls of the heating furnace. . The heating burner 40 arranged in the lower region of the furnace extraction end is also arranged as a pair of parners 40a and 40b.

In order to extract the material to be heated heated by the heating furnace to the outside of the furnace, when the extraction door 3a of the heating furnace is opened, the combustion of the heating parners 40a and 40b is controlled independently. As shown in Fig. 2A and Fig. 2B, while the extraction door 3a is open, the panner frames of the heating parners 40a and 40b extend in the width direction of the extraction port 3b over the opening width. Perform combustion operation. If a wrench frame is formed over the width of the opening of the outlet 3b in this way, the air that has entered the furnace from the outlet 3 is first blocked by the wrench frame and cannot enter the furnace further. . In addition, since the oxygen of the intruding air is consumed by the perna frame, an increase in the oxygen concentration in the furnace due to the intruding air is avoided.

In particular, as shown in Fig. 14, in an extraction door having a comb-shaped extract rough oak opening 3c below the extraction opening 3b, air tends to enter through the extract rough oak opening 3c. It is extremely effective to block the air entry path with the burner frames of the heating parners 40a and 40b located in the lower part of the furnace extraction end. If heating parners are not arranged in pairs, combustion control may be performed by extending the parner frame of a single heating parner in the furnace width direction.

Here, the formation position of the burner frame of the heating parners 40a and 40b In the furnace length direction, it is preferable that the perna frame is as close as possible to the extraction port as far as possible without touching the structure below the extraction port. On the other hand, it is preferable to set the position where the perna frame can block the opening of the extra rough oak in the height direction of the furnace and within the range that does not touch the hearth.

As shown in Fig. 15, a partition wall 8 rising from the hearth is provided inside the furnace of the heating parners 40a and 40b, and the heating parners 40a and 40b are provided. It is preferable to block the air entry path with the above-mentioned wrench frame.

Here, as shown in Fig. 15, the pressure distribution inside the furnace is positive with respect to the pressure outside the furnace (substantially atmospheric pressure) at the upper part, and negative at the lower part with the transfer path 6 as the boundary. Pressure. In other words, in a normal furnace, the draft becomes larger as it goes down, so that the furnace pressure shows a distribution that becomes lower as it goes down. In such a heating furnace, if the entire area inside the furnace is set to a positive pressure, the pressure in the upper part of the furnace becomes higher and as a result, the gas in the furnace may be ejected from each opening. For this reason, the damper 7b (see FIG. 1) controls the furnace pressure at the height of the transfer path 6 to be equal to the atmospheric pressure.

The air that has entered through the extraction opening 3b, particularly through the extra trough oak opening 3c, travels toward the lower part of the transport path 6 and is mostly taken into the heating parners 40a and 4Ob. Since the temperature of the intruding air is lower than the temperature inside the furnace, a part of the intruding air once flows into the hearth, as shown by the broken line in Fig. 15. Since this intruding air travels deep inside the furnace from the back side of the heating parners 40a and 40b, it easily enters the furnace, albeit little.

When the partition wall 8 is provided, the air that has entered from the back side of the heating parners 40 a and 40 b is blocked by the partition wall 8. Here, it is gradually warmed and becomes ascending flow along the partition wall 8 to reach the positive pressure region at the upper part of the transfer path 6, and is discharged from the furnace from the upper part of the transfer path 6. In this way, it is possible to prevent air that has entered from the back side of the heating parners 40a and 40b from entering the furnace. In addition, in order to cut off the air intrusion path with the parner frame of the heating parners 40a and 40b, the heating parners 40a and 40b must be operated under combustion at a low air ratio. Is preferred. Fig. 16 shows the relationship between the air ratio in the heating end of the extraction end and the amount of air that has penetrated in the heating end. It is clear that the lower the air ratio in the heating parner, the greater the amount of ingress air burned in the heating parner. If the heating parners 40a and 40b are operated under a low air ratio, the oxygen in the air that has entered through the extraction port 3b can be immediately burned and consumed, and the furnace atmosphere can be reduced. It is effective for keeping low oxygen concentration. The partition wall 8 has a width extending between both side walls of the furnace, and it is advantageous to increase the partition wall 8 so that the partition wall 8 does not interfere with the transfer devices in the furnace from the hearth.

Fig. 4 shows the exhaust gas discharge route in a continuous heating furnace used directly in the method of the present invention. A pipe is connected between the flue 7 and the path 45 from the wrench 40a or 40b shown in Figs. 2A and 2B to the suction device 8 shown in Fig. 4 via the heat storage element 42a or 42b. Road 10 is established. A piping 10 that guides the exhaust gas in the flue 7 to the suction device 8 through the on-off valve 9 is provided between the inlet side of the suction device 8 and the flue 7 that guides the exhaust gas in the heating furnace out of the furnace. There is a characteristic at the time. In the path 45, on the inlet side of the suction device 8, and on the upstream side of the connection of the pipe line 10, the flow rate for measuring the amount of exhaust gas suctioned from the wrench to determine the opening / closing timing of the on-off valve 9 A total of 45a will be provided. In addition, a flow control valve 45 b for adjusting the total flow to a predetermined amount is provided between the connection between the pipe 10 and the path 45 and the suction device 8.

In a heating furnace equipped with the above exhaust gas discharge path, if the suction load 8 is operated at a load of, for example, less than 10% due to a reduction in the combustion load of the regenerative parner, the on-off valve 9 Is opened to guide the exhaust gas in the flue 7 to the inlet of the suction device 8 in the route 45 to increase the operating load of the suction device 8.

Specifically, when the flue gas in flue 7 was led to route 45, The exhaust gas temperature after mixing with the low-temperature exhaust gas that has passed through the heat storage unit does not exceed the upper limit of the durable temperature of the suction device 8, especially the impeller. The diameter of the pipe 10 is selected to control the flow rate of the exhaust gas, and at the same time, the pressure loss between the exhaust gas in the flue at the mixing point and the low-temperature exhaust gas passing through the regenerator is equalized, and the mixed exhaust gas is guided to the suction device 8.

By this operation, it is possible to easily increase the operating load of the suction device 8 to, for example, 10% or more, and to solve the above-described problems in the extremely low load combustion.

Next, the supply of flue gas in the flue via the pipe line 10 is stopped when the amount of suction from the wrench exceeds the required minimum flow rate. That is, the on-off valve 9 of the piping line 10 is closed. The required minimum flow rate is the lower limit of the stable operation area when designing the fan.

The flow rate control of the exhaust gas guided to the suction device 8 can also be performed by using the opening / closing valve 9 of the pipe line 10 as a flow rate adjusting valve. However, the operation of the flow control valve is complicated, the mechanism is complicated, and the equipment cost is high. In the present invention, a simple method of simply opening and closing the pipe line 10 having a predetermined pipe diameter is employed.

Here, the pipe diameter of the pipe 10 can be designed, for example, according to the following equations (A) and (B).

Record

(Exhaust gas dew point) ≤ T _a ≤ T b —— (A)

Δ Ρ 1 = Δ Ρ 2 (Β)

However,

Τ _a : Temperature of mixed exhaust gas where V2 = V1 + V3

T b: Suction device (represented by a bearing) Endurance temperature upper limit

«,

V I: Exhaust gas suction volume at minimum burner (extremely low load)

V2: Required minimum flow rate of exhaust gas for stable operation of the suction device

V3: V2—The amount of exhaust gas to compensate for the difference between VI ΔP 1: Pressure loss between the wrench on the line 45 and the line junction ΔP 2: Pressure loss on the line 10

As shown in Fig. 4, a recuperator 7a is provided upstream of the pipe 10 of the flue 7. It is preferable to supply the cooled exhaust gas to the piping 10 by passing the exhaust gas in the furnace through the recuperator 7 a in order to extend the durable life of the suction device 8.

In the above embodiment, the flue gas in the heating furnace is not directly mixed with the flue gas from the furnace, but the flue gas in the flue is mixed.

The gas to be mixed with the flue gas from the burner is not limited to the flue gas, but may be a high-temperature gas, that is, hot air. For example, air heated to a high temperature may be used, or a separate combustion device may be provided, and the combustion exhaust gas generated therefrom may be mixed.

As shown in FIGS. 2A and 2B, in the regenerative burner, the exhaust gas sucked from the burner 40a or 40b is guided to the outside of the furnace through the shared passage 41a or 41b. The exhaust gas is sucked along the route shown in Fig.17. That is, the combined passages 41a and 41b extending from a plurality of sets of regenerative parners are combined into exhaust gas ducts 8a and 8b provided for each parner group on one side and the other side of the furnace wall, respectively. Then, these exhaust gas ducts 8a and 8b are combined into one conduit 9, and this conduit 9 is connected to the flue 7 of the heating furnace via the suction fan 10. Then, by the suction force of the suction fan 10, the exhaust gas is guided to the flue 7 through the shared passages 41a and 41b, the exhaust gas ducts 8a and 8b, and the conduit 9, and discharged out of the furnace. ing.

In the exhaust gas discharge path described above, the probe 11 is inserted in the middle of the conduit 9 in the example shown in FIG. A part of the exhaust gas flowing from the probe 11 through the conduit 9 is sampled, and the concentration of various components is measured using the analyzer 12 with respect to the sampled exhaust gas. The various measured concentration values obtained in this way show a good distribution of the furnace atmosphere, especially in the furnace width direction. This is heat storage It can be used as a representative value of the component concentration at the position in the furnace where the open-end wrench is installed, for example, in the solitary zone 3.

Here, the case where the oxygen concentration was measured by searching for the exhaust gas sucked from the regenerative parner and the case where the oxygen concentration was measured via a probe inserted from the furnace wall were compared with the average oxygen concentration in the furnace. The error was investigated. Figure 18 shows the results. When the oxygen concentration was measured by collecting the exhaust gas sucked from the regenerative parner, it was found that the difference from the actual average oxygen concentration in the furnace was extremely small. In other words, the actual concentration of components in the furnace atmosphere can be measured by examining the exhaust gas sucked from the regenerative parner. The average oxygen concentration in the furnace refers to the gas flow rate and gas flow into the wrench under the condition that the extraction door and the charging door are closed and the furnace pressure is set so that the air entering the furnace is O Nm / h. This is a calculated value theoretically obtained from the component / air ratio. Other conditions will be described in detail in Examples described later.

As shown in Fig. 17, it is desirable that the location where the exhaust gas sucked from the regenerative parner is collected is located downstream of the regenerator of the regenerative parner. The exhaust gas from which heat is recovered by the heat storage body is naturally lower than the furnace temperature. If a probe is introduced downstream of the heat storage body, the probe will not be exposed to a high-temperature atmosphere, and its durable life can be extended.

In the above case, the case where a continuous heating furnace is used has been described. However, the present invention can be applied to a patch heating furnace / a rotary hearth heating furnace. Example 1

Using a continuous heating furnace (transport path height: 0.5 m from the furnace bottom) shown in Fig. 5, a steel slab with a thickness of 220 mm, a width of 1200 mm and a length of 9800 mm was introduced, and 1230 ° from room temperature. An operation of heating to C was performed. The specifications of the four sets of regenerative parners arranged in the soaking zone of the heating furnace are as follows.

Record

Combustion capacity: 20000000 (kcal / H · Pana)

Combustion switching time between pair of wrench: 60 s / time Exhaust gas suction rate: 0.4 to 0.8 (_)

In the operation of the heating furnace, as shown in Table 1, the furnace pressure was controlled by variously adjusting the exhaust gas suction rate from the wrench according to the combustion load of the entire heating furnace. For comparison, conventional operations were also performed with a constant exhaust gas suction rate. As a result, it becomes possible to stably control the furnace pressure under various combustion load conditions in the actual operation of the heating furnace, and as shown in Table 2, the oxygen concentration in the furnace is larger than in the conventional method. The fuel consumption rate and the defect rate of slabs were reduced.

Figure 7 shows the relationship between the furnace pressure at the lower part of the tropical zone and the amount of air entering in the above operation on average.

Example 2

Using a continuous heating furnace (transfer path height: 0.5 m from the furnace bottom) shown in Fig. 8, a steel slab with a thickness of 220 mm, a width of 1200 mm and a length of 9800 mm was introduced, and the room temperature was reduced from room temperature. An operation of heating to 1 230 ° C was performed. The operating conditions are as follows.

Record

Heating furnace (Pana) Combustion load: 10-100%

Die Li Yushiyo N'ea flow ^{rate: 0~ 50000 (Nm 3 / H} )

Exhaust gas temperature at the inlet of the recuperator: 750 Ό or less

Flue damper opening: 5-100%

In the operation of the heating furnace described above, if the exhaust gas temperature at the inlet of the recuperator becomes 750 ° C or more, or if the furnace pressure in the lower part of the solitary tropics becomes O mmAq or less, the dilution air is released. The gas was supplied under the condition that the exhaust gas temperature at the inlet of the recuperator was 750 ° C and the pressure in the soaking lower furnace was> 0 mmAq. In comparison, operations without furnace pressure control using dilution air were also performed.

In these operations, when the combustion load of the heating furnace was varied, the furnace pressure in the lower part of the solitary tropics and the oxygen concentration in the same area were measured with the extraction door closed. As shown in Fig. 10, the measurement results By controlling the furnace pressure by using the partition air, the furnace pressure could be maintained at a positive pressure and the oxygen concentration could be maintained at a low level. On the other hand, in the conventional furnace pressure control using only a damper, both the furnace pressure and the oxygen concentration changed greatly.

Next, in the same operation, the furnace pressure and oxygen concentration when the extraction door was opened and closed were measured in the same manner. As shown in Fig. 11 and Fig. 12, the measurement results show that even if the extraction door is opened and closed, the furnace pressure is controlled by the dilution air to make the furnace pressure positive. And the oxygen concentration can be maintained at a low level.

Example 3

In the continuous heating furnace shown in Fig. 1, operation was performed to heat steel slurp from room temperature to 1150 ° C. Then, when the heated steel slab was extracted from the extraction door 3a, the heating parners 40a and 40b at the extraction end were burned under the conditions shown in Table 3. In addition, in a continuous heating furnace shown in Fig. 1, a partition wall 8 shown in Fig. 15 was provided according to the following specifications. Extracted. In addition, as a comparison, a conventional furnace operation in which the heating parners 40a and 40b at the extraction end were burned under the same conditions as the other heating parners 4 was also performed.

Table 3 also shows the results of the measurements of the amount of air entering the furnace and the oxygen concentration in the atmosphere in the solitary tropics in the various operations described above.

Record

Partition wall height: 1.2 m from the hearth.

Width: Same width as furnace width

Example 4

Using the continuous heating furnace shown in Fig. 1 (transport path height: 0.5 m from the furnace bottom), a steel slab with a thickness of 220 mm, a width of 1200 mm and a length of 9800 mm was introduced, and from room temperature to 1230 mm The operation to heat up was performed. The specifications of the four sets of regenerative parners arranged in the soaking zone of the heating furnace are as follows.

Record Combustion capacity: 2,000,000 (kcal / H · Pana)

Combustion load: 10-100%

Combustion switching time between pair of wrench: 60 s times

Exhaust gas suction rate: 60 to 90%

In the operation of the heating furnace described above, after the exhaust gas sucked from the regenerative parner was passed through the regenerator, a part of the exhaust gas was sampled from the probe 11 inserted in the middle of the conduit 9, and the collected exhaust gas was analyzed by the analyzer 12 The oxygen concentration was measured using. The measurement range of the oxygen concentration in the furnace was 0 to 21 vol%, and the atmosphere temperature in the pipe 9 was 200 ° C. As a comparison, the oxygen concentration was measured via a probe inserted from the hearth of the tropical zone.

The results of comparing these measured concentration values with the average oxygen concentration in the furnace are shown in FIG. 18. When the measurement was performed using the exhaust gas sucked from the regenerative parner according to the present invention, the average oxygen concentration in the furnace was measured. The deviation from the value was less than 0.5%. On the other hand, when the oxygen concentration was measured through a probe inserted from the furnace wall, the error from the average oxygen concentration in the furnace was 1-3%. Industrial applicability

As described above, according to the present invention, the furnace pressure can be strictly controlled. This furnace pressure control can reliably prevent air from entering the heating furnace from the extraction door. The deterioration of the quality of the material to be heated can be prevented. The unit fuel consumption in the heating furnace can be improved. According to the present invention, the operation of the exhaust gas suction device does not become unstable even when the combustion load of the regenerative burner is small. Since no drain is generated, the operation of the heating furnace is stabilized. According to the present invention, the concentration of components in the atmosphere in the heating furnace can be accurately measured. By controlling the furnace atmosphere based on these measurements, high-quality products can be produced. Further, the method for measuring the component concentration in the atmosphere in the heating furnace according to the present invention can be performed using existing equipment, so that new equipment investment is not required and the method can be realized at low cost. Inventive example Conventional example Entire heating furnace

Operational combustion load Exhaust gas Lower tropical zone Exhaust gas Lower tropical zone

(%) Suction rate Furnace pressure Suction rate Furnace pressure

(One) (mmAq) (One) (mmAq)

1 2 0 0 .4 0 0 .8 1 1 .4

2 3 0 0 .4 0 0 .8 1 1 .0

3 4 0 .0.5 0 0 .8 1 0 .7

4 5 0 .0.5 0 .10 0 .8 1 .5

5 6 0 0 .6 0 .1 0 .8 1 0 .3

6 7 0 .0.6 0 .2 0 .8 1 0 .1

7 8 0 0 .7 0 .2 0 .8 0

8 9 0 0 .7 0 .3 0 .8 0 .1

9 1 0 0 0 .8 0 .3 0.8 .3

Table 2

(*) Displayed as an index when the result of the conventional example is set to 1.

(The smaller the number, the better the performance)

Table 3

Operation Combustion load (%) Air ratio

Partition wall Air volume Remarks Extraction end Others Extraction end Others (Nm ³ / H)

Nonna Pana Pana Pana

1 100 80 0.8 0.8 1.05 500 ≤ 1.0 Invention example

2 100 50 0.8 0.105 600 ≤ 1.5 Invention example

3 100 50 0.8 0.15 Yes 300 ≤ 1.0 Invention example

4 60 1.0 5000 5 to 10 Conventional example

Claims

The scope of the claims

1. Pre-tropical zone, heating zone, and solitary zone, and as the heat source of the solitary zone, a plurality of regenerative pans, which are arranged with a pair of panes provided with a heat storage body facing each other, are arranged. In a heating furnace, each pair of regenerative parners is burned alternately, and when not burning, the exhaust gas in the furnace is sucked from the parner during non-combustion, and the exhaust gas is introduced into the regenerator to transfer the heat in the exhaust gas to the regenerator. The collected heat is used to add heat to the combustion air in the burner during combustion, and the furnace is operated in accordance with the combustion load of the entire heating furnace. A furnace pressure control method using a regenerative parner, characterized by controlling the furnace temperature in a tropical zone by adjusting the exhaust gas suction rate into the furnace.

2. A recuperator is placed in the flue that guides the exhaust gas from the heating furnace to the outside of the furnace. When the recuperator preheats the combustion air supplied to the burner heating source, the recuperator is heated to a high temperature. In order to protect the atmosphere, the supply of diluent air to the recuperator inlet side of the flue depends on the exhaust gas temperature at the recuperator inlet side and the combustion load of the heating furnace. A furnace pressure control method for a heating furnace, comprising adjusting a furnace flow rate and controlling a furnace pressure.

4. In claim 3, a partition wall rising from the hearth is provided inside the furnace of the heating parner arranged at the furnace extraction end to form an upward flow along the partition wall, and the air that has entered through the extraction port is discharged. Heating characterized by being placed on an upward flow Furnace atmosphere control method.

5. The method for controlling the atmosphere of a heating furnace according to claim 3, wherein the heating parner arranged at the furnace extraction end is operated under a low air ratio.

6. In a heating furnace, which has a regenerative parner with a pair of parners with a heat accumulator facing each other as a heating source, in the heating furnace, the parners of each pair of the regenerative parners are alternately burned, and Exhaust gas in the furnace is sucked from the burner through the furnace, the exhaust gas is introduced into the regenerator, heat in the flue gas is collected in the regenerator, and the recovered heat is used to heat the combustion air of the burner during combustion. In operating the heating furnace, when the combustion load of the regenerative burner is small, the suction device for sucking exhaust gas from the furnace through the regenerator from the non-burning burner is used. A method for operating a heating furnace having a regenerative parner, characterized by supplying hot air.

7. The operating method of a heating furnace according to claim 6, wherein the hot air is an exhaust gas in a flue that guides an exhaust gas in the heating furnace out of the furnace.

8. In a heating furnace, which has a regenerative parner with a pair of parners provided with a heat accumulator facing each other as a heating source, the parners of each pair of the regenerative parners are alternately burned in a heating furnace. Exhaust gas in the furnace is sucked from the furnace during combustion, the exhaust gas is introduced into the regenerator, heat in the exhaust gas is collected in the regenerator, and the recovered heat is used to heat the combustion air of the parner during combustion. When operating the heating furnace using the furnace, a part of the exhaust gas sucked from the above-mentioned wrench is guided to an analyzer to measure the concentration of components in the exhaust gas. How to measure gas concentration.

9. The component concentration of the exhaust gas sucked from the regenerative parner according to claim 8. A method for measuring the concentration of an atmospheric gas in a heating furnace, wherein the measured value is used as a representative value of the component concentration in (1) in the heating furnace provided with the regenerative parner.

10. As a heat source, a plurality of regenerative parners are provided opposite to each other with a pair of panners provided with a heat storage element, and the burners of each pair of the regenerative parners are alternately burned. In addition, the exhaust gas in the furnace is sucked from the burner during non-combustion, the exhaust gas is introduced into the heat accumulator, heat in the exhaust gas is collected in the heat accumulator, and the recovered heat is used for the combustion air of the burner during combustion. In a heating furnace that operates using heating, at least the regenerative parner arranged at the lower part of the extraction end of the furnace has a combustion control system independent of other regenerative parners. Heating furnace.

11. The claim 10, wherein a partition wall rising from the hearth is provided at a position where the regenerative pan having an independent combustion control system is sandwiched between the heating furnace and the extraction door. heating furnace.

1 2. As a heat source, a regenerative parner is provided with a pair of panners provided with a heat storage element facing each other, and the parners of each pair of the regenerative parners are alternately burned and non-burned. Exhaust gas in the furnace is sucked from the furnace at the time of introduction, the exhaust gas is introduced into the heat storage body, heat in the exhaust gas is recovered to the heat storage body, and the recovered heat is used for heating the combustion air of the parner during combustion. In a heating furnace, a suction device is disposed at an end of a path for sucking exhaust gas in the heating furnace from a non-combustion burner through a heat storage body, and a suction device is provided on the suction device entrance side of the path. A heating furnace provided with a piping path for guiding hot air to a suction device through an on-off valve.

1 3. The pipe line is connected to a flue that guides exhaust gas inside the heating furnace to the outside of the furnace, and guides the exhaust gas inside the heating furnace as hot air. 13. The heating furnace according to claim 12, wherein

14. The heating furnace according to claim 12, wherein a recuperator is provided on an upstream side of a flue pipe.

15 5. As a heating source, a regenerative parner is provided with a pair of parners with heat storage elements attached to each other, and the parners of each pair of the regenerative parners are alternately burned and non-burned. Exhaust gas in the furnace is sucked from the furnace at the time of introduction, the exhaust gas is introduced into the heat storage body, heat in the exhaust gas is recovered to the heat storage body, and the recovered heat is used for heating the combustion air of the parner during combustion. In a heating furnace, a part of the exhaust gas is sampled in the course of discharging the exhaust gas in the heating furnace from the non-combustion burner through a heat storage unit, and a probe is used to collect the exhaust gas. A heating furnace provided with an analyzer for measuring the concentration of each component.